Makindo Medical Notes

👁️🧠 Miller Fisher Syndrome (MFS) is a rare variant of Guillain-Barré Syndrome (GBS), strongly associated with anti-GQ1b antibodies. Unlike typical GBS, it primarily affects the eyes and coordination rather than causing widespread limb weakness.

About

• 🔹 Accounts for ~5% of Guillain-Barré cases.
• 🔹 Defined by the classic triad: ophthalmoplegia, ataxia, and areflexia.
• 🔹 Weakness is usually absent, distinguishing it from typical GBS.
• 🔹 Often post-infectious (e.g., following Campylobacter jejuni or viral illness).

Clinical Features

• 👀 Ophthalmoplegia: Diplopia and restricted eye movements, often the first presenting symptom.
• ⚖️ Ataxia: Gait imbalance and impaired coordination, usually without limb weakness.
• 🔔 Areflexia: Absent tendon reflexes despite preserved motor strength.
• 😀 Cranial nerve involvement may cause mild facial weakness or bulbar symptoms.
• ❗ Rarely, symptoms can progress into classical GBS with limb or respiratory involvement, so monitoring is vital.

Differential Diagnosis

• 🎯 Myasthenia Gravis (MG): Fluctuating weakness, no areflexia.
• 🧴 Botulism: Ocular involvement but descending paralysis and autonomic dysfunction dominate.
• 💉 Diphtheria: Cranial neuropathies but with systemic illness.
• 🕷️ Tick paralysis: Ascending paralysis, history of tick bite.
• 🌸 Sarcoidosis: Granulomatous cranial neuropathies, with systemic signs (lungs, skin, eyes).

Investigations

• 🧪 Anti-GQ1b antibodies: Positive in ~90% – highly specific for MFS.
• 💉 CSF: Albuminocytologic dissociation (↑protein, normal WCC) similar to GBS.
• ⚡ EMG/Nerve Conduction Studies: May show mild demyelination, less than in typical GBS.
• 🩻 Neuroimaging (MRI brain): Performed to rule out brainstem pathology if atypical features.

Management

• 💉 IV Immunoglobulin (IVIg): Mainstay therapy, accelerates recovery.
• 🔄 Plasma Exchange: Alternative to IVIg, useful in severe or progressive disease.
• 🫁 Supportive Care: Monitor for respiratory compromise, as ~5% progress to classical GBS.
• 🦵 Rehabilitation: Physiotherapy and occupational therapy aid recovery and function.

Prognosis

• 🌟 Generally excellent – most recover fully within 8–12 weeks.
• 🧪 Anti-GQ1b positivity is both a diagnostic and prognostic marker.
• ⚠️ Relapse is rare but can occur; long-term disability is uncommon.

Cases — Miller–Fisher Syndrome

• Case 1 — Classic Triad 👁️: A 40-year-old man presents 2 weeks after a flu-like illness with double vision, unsteady gait, and numbness around his mouth. Exam: bilateral ophthalmoplegia, ataxia, and areflexia. Limb strength is preserved. Diagnosis: Miller–Fisher syndrome. Management: Admit for monitoring; IV immunoglobulin (IVIG); supportive physiotherapy. Prognosis usually excellent.
• Case 2 — Bulbar Involvement 🗣️: A 55-year-old woman develops progressive diplopia, slurred speech, and unsteadiness. Exam: ophthalmoplegia, dysarthria, limb areflexia, wide-based gait. Anti-GQ1b antibodies positive. Diagnosis: MFS with bulbar involvement. Management: IVIG; swallowing assessment; neuro-rehab input; monitor for respiratory decline.
• Case 3 — Overlap with GBS ⚡: A 33-year-old man presents with acute diplopia and ataxia after diarrhoeal illness. Over days, he develops mild ascending limb weakness in addition to the triad. CSF: albuminocytologic dissociation. Diagnosis: Miller–Fisher syndrome overlapping with Guillain–Barré syndrome. Management: IVIG or plasma exchange; respiratory monitoring; MDT rehabilitation.

Teaching Commentary 🧠

Miller–Fisher syndrome is a rare GBS variant, typically presenting with the triad of ophthalmoplegia, ataxia, and areflexia, but with preserved limb strength. - Often follows infection (Campylobacter, viral). - Anti-GQ1b antibodies strongly associated. - CSF: albuminocytologic dissociation (raised protein, normal cells). - NCS: reduced sensory action potentials, abnormal brainstem reflexes. Management = IVIG or plasma exchange + supportive therapy. Prognosis is usually good, with recovery in weeks–months.